[Proteolysis of human proinsulin catalysed by native, modified, and immobilized trypsin]. / Proteoliz proinsulina cheloveka, kataliziruemyi nativnym, modifitsirovannym i immobilizirovannym tripsinom.

Proteolysis of recombinant human proinsulin by the native trypsin, by trypsin modified with a copolymer of vinylpyrrolidone and acrolein, and by the same modified trypsin immobilized on Silochrom 1.5 was studied by RP HPLC and mass spectrometry. Rate constants of the main stages of proinsulin hydrolysis by the native trypsin were estimated. The values of rate constants of the digestions of the most easily hydrolyzable bonds (those formed by the pairs of the basic amino acid residues) in proinsulin were found to be of the same order as those formed by the separate lysine residues (Lys7) and those formed by the four basic amino acid residues of the C-terminal cluster of melittin. It was established that covalent trypsin binding to the copolymer did not change the ratio of the rate constants of the individual stages of proinsulin hydrolysis, whereas after the immobilization of modified trypsin on the Silochrome, the formation of diarginyl insulin-ArgArg, intermediate forms of hydrolyzed insulin, and desThr-insulin proceeds with comparable rates.

[ECP 32 proteinase: characteristics of the enzyme, study of specificity]. / Proteinaza ECP 32: kharakteristika fermenta, issledovanie spetsifichnosti.

Hydrolysis of the C-peptide from recombinant human proinsulin, porcine insulin, and melittin by the E. coli actin-degrading proteinase ECP 32 was studied by reverse phase high performance liquid chromatography and mass spectrometry with electrospray ion source. Proteinase ECP 32 hydrolyzed only melittin at the Ala15-Leu16 or Leu16-Ile17 bonds (KM = 2.4 x 10(-6) M). The effects of pH and buffer composition on the rate of enzymatic hydrolysis were studied. The pH optimum of melittin hydrolysis was 7. Phosphates inhibited, whereas ATP stimulated the hydrolysis of melittin. Melittin was suggested as a substrate for determining the activity of proteinase ECP 32.

[A comparative study of the effect of inhibitors of microbial origin on different alpha-glucosidases]. / Sravnitel'noe izuchenie deistviia ingibitorov mikrobnogo proiskhozhdeniia na razlichnye alpha-gliukozidazy.

The action of a new alpha-glucosidase inhibitor from Streptomyces sp. and Acarbose on alpha-glucosidases of various origins has been studied. Differences in specificity, efficiency, nature and type of inhibition of microbial glucosidases and some enzymes of the small intestine mucosa by the biologically active substances studied were revealed. At certain concentrations these inhibitors can be substrates for some intestinal glucosidases. It is suggested that the inhibitor from Streptomyces sp. (in combination with a diet) can be used for regulation of some disturbances in carbohydrate metabolism.

[Yeast superoxide dismutase: isolation and properties (review of the literature)]. / Superoksiddismutaza drozhzhei: vydelenie i svoistva (obzor).

Modern data are reviewed on isolation procedures and properties of superoxide dismutase from Saccharomyces cerevisiae. Properties of superoxide dismutase (SOD) from yeast and SOD from macro-organisms were compared.

[The effect of lipase from Penicillium sp. on the membrane fraction of the levorin-producing Streptomyces levoris]. / Deistvie lipazy Penicillium sp. na membrannuiu fraktsiiu produtsenta levorina Streptomyces levoris.

The effect of a lipase preparation from Penicillium sp. on the membranes of the levorin producer Streptomyces levoris was being studied. The enzyme preparation was found preferably to hydrolyse neutral lipids in the Str. levoris membranes, which makes it possible to use the lipase from Penicillium sp. for studying neutral lipids in microbial membranes.

[Lipolytic complex of Penicillium sp]. / Izuchenie lipoliticheskogo kompleksa Penicillium sp.

By gel filtration on Sephadex G-75 it has been demonstrated that the lipolytic complex of Penicillium sp. contains two active components--a high molecular weight (lipase-1) and low molecular weight component (lipase-2). Both components have been isolated by Sephadex gel-filtration and DEAE-cellulose chromatography. It has been shown by discelectrophoresis and isoelectric focusing that lipase-2 is a highly purified protein with the molecular weight of 30,000 (gel-filtration) or 29,000 (electrophoresis) and isoelectric point at pH 4.8 Lipase-1 has been found to contain large quantities of lipids. The conditions of deaggregation of a high molecular weight component have been identified to yield a new active component corresponding to lipase-2 in its gel-filtration and disc-electrophoresis properties. It has been shown that pH 7.5-8.0 and temperature 37-40 degrees are optimal for both lipase-1 and lipase-2. Activities of the two components are inhibited by Na deoxycholate and remain unchanged in the presence of Na cholate and dehydrocholate. On the basis of these findings it is concluded that lipase-1 and lipase-2 are two forms of the same enzyme.

[Isolation and characterization of lipase from Geotrichum asteroides FKM F-144]. / Vydelenie i nekotorye svoistva lipazy Geotrichum asteroides VKM F-144.

By gel chromatography on Sephadex G-75 it has been demonstrated that the culture fluid of Geotrichum asteroides VKM F-144 contains two lipolytic components, one of which, lipase 1, eluates in the free volume of the column, whereas the second component, lipase 2, eluates in the volume close to that of the egg albumin yield. The paper describes a method for lipase 2 preparation consisting of precipitation of accompanying compounds at pH 4.2, depigmentation of the supernatant on the resin PAP in the Cl-form, selective sorption of lipase on the cation exchange resin CMC and further purification of the eluate gel chromatography and Sephadex G-100 rechromatography. The molecular weight of the lipase is estimated to be 45,000 and the isoelectric point to correspond to pH 4.3. pH optimum of action of the purified enzyme, areas of its pH- and thermostability have been determined.

[Isolation of lipase of microbial origin]. / Vydelenie lipazy mikrobnogo proiskhozhdeniia.

By gel chromatography and polyacrylamide gel disc-electrophoresis the component composition of the culture liquid separated from the mycelium was investigated. After elution from Sephadex G-75 column lipase activity was concentrated in one peak. Out of 13 electrophoretic mobile protein components only one split trioleate. The paper describes a method to isolate lipase from the native solution of the produced which involves enzyme precipitation at 40% saturation of the native solution with ammonium sulphate, dialysis of the resultant concentrate and selective sorption of pigment and protein admixtures on the cellulose anion exchanger. The method maker it possible to obtain a highly purified lipolytic enzyme with a specific activity of up to 15 000 lu/mg protein and to provide its 35--40% yield.

[Comparative study of the properties of lipase of microbial origin]. / Sravnitel'noe izuchenie svoistv lipaz mikrobnogo proiskhozhdeniia

A comparative study of properties of lipases of microbial origin has shown that the pH optimum of the enzymes from Geotrichum asteroides and Penicillium sp. is at pH 7.5 and 5.0, respectively. Lipase from Geotrichum asteroides appears more resistant to high temperatures and pH changes than the enzyme from Penicillium sp. Both enzymes split selectively vegetable oils, especially cotton and sunflower oils. Na cholate and deoxycholate at a concentration of 0.05-0.4% act as hydrolysis activators, particularly with respect to Geotrichum lipase. Na dehydrocholate does not show this effect.